Strand twisting apparatus



Nov. 3, 1959 1'. T. BUNCH STRAND TwIsTING APPARATUS 3 Sheets-Sheet 1Filed July 22, 1955 INVENTOR.

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Nov. 3, 1959 STRAND TwIsTING APPARATUS Filed July 22, 1955 RNE Y Nov. 3,1959 r. T. BUNCH STRAND TwIsTING APPARATUS 3 Sheets-Sheet 3 Filed July22, 1955 INVENTGR.

72 7'. BUNCH av l ArroRA/Ev United States Patent Ofllce amasar PatentedNov. 3, 1959 STRAND TWISTING APPARATUS Tillman T. Bunch, near Ashland,Baltimore County, Md., assignor to Western Electric Company,Incorporated, New York, N.Y., a corporation of New York Application July22, '1955, Serial No. 523,911 '10 Claims. (Cl. 57-58.52)

This invention relates to strand twisting apparatus and moreparticularly to apparatus for twisting a plurality of strands togetherinto a single compact cable.

In the use of conventional strand twisting apparatus, in which a pair ofspaced flyers are rotated at opposite ends of a reel-supporting cradlefrom which strands are withdrawn and twisted into a cable, considerabledifllculty has arisen previous due to the tension necessary `to restrictthe ballooning of a normally unsupported length of the cable passingbetween sheaves on the outer ends of the rotating flyer arms -to withinworkable limits. Due to centrifugal forces, this ballooning of the cableincreases as the rotational speeds of the flyer arms are increased and,accordingly, imposes serious limitations upon the operating speeds ofconventional strand twisting apparatus because of the danger of breakageor fouling of the cable.

The problem becomes more acute when such strand twisting apparatus isdesigned to accommodate strand supply reels of relatively largedimensions to obtain longer continuous production runs. To allow ytheloading and unloading of such large strand supply reels, the design ofconventional stranding apparatus necessitates relatively long spanswhich the cable must traverse, thereby aggravating the problem ofrestricting the ballooning at high speed operation.

In conventional bow type stranders, tube type stranders `or variants ofthese types, rotating cable supporting means incur the same detrimentalcentrifugal loading that the cable experiences and must rely either onloaded beam structures or on catenary type tension members to supportthe centrifugal loading. lt is recognized generally that thesestructures develop inherently much greater stresses under centrifugalloading than are developed in hoop-like structures.

It is an object of this invention to provide new and improved strandtwisting apparatus.

It is another object of this invention to provide new and improvedapparatus for twisting a plurality of strands together into a singlecompact cable.

Apparatus embodying certain features of this invention may include astrand supply, means for withdrawing a strand from the strand supply,rotatable means for carrying a loop of the strand rotatably about thestrand supply as the strand is withdrawn therefrom, and a rotatable hoopmounted concentrically with respect to the rotational axis of therotatable means for engaging the strand loop and restraining theballooning thereof.

In a specific embodiment of this invention, a plurality of spaced,circular hoops are positioned between the rotating flyer arms of aconventional strand twisting apparatus. The internal diameters of thehoops are such that they tend to restrain the ballooning of the lengthof the cable passing between guide sheaves on the extremities of therotating flyer arms. The hoops are supported concentrically with respectto the common rotational axis of the rotating flyer arms and are drivenin synchronism with :the flyer arms so that there is substantially norelative rotational movement between the hoops and the advancing cableat the points of contact therebetween. The hoops function to restrainthe ballooning of the cable between the flyer arms and reduce thetensional stresses in the cables created by centrifugal forces.

A complete understanding of the invention may be had from the followingdetailed descriptions of apparatus forming specific embodiments thereof,when read in conjunction with the appended drawings, in which:

Fig. 1 is a side elevation of strand twisting apparatus embodying theinvention;

Fig. 2 is an enlarged, side elevation of a flyer unit forming a part ofthe strand twisting apparatus illustrated in Fig. l, with parts thereofbroken away for clarity;

Fig. 3 is a vertical section taken along line 3-3 of Fig. 2;

Fig. 4 is a fragmentary, end elevation of a hoop forming a part of amodified embodiment of the invention, and

Fig. 5 is an enlarged vertical section taken along line 5--5 of Fig. 4.

Referring now to Fig. l, there is shown strand twisting apparatus whichincludes a flyer unit, indicated generally at 10, and a takeup unit,indicated generally at 12. Both of these units are driven by a motor 14through a conventional gear reducer 15 designed to rotate a drive shaft16 journalled rotatably in antifriction bearings 17-1'7. The takeup unit12 comprises a takeup capstan 2li and a takeup reel 21 which areconnected to the driven shaft 16 through conventional transmission means(not shown) so that the takeup capstan and takeup reel are driven by themotor 14 at predetermined speeds and in timed relation with one anotherand the flyer unit 10.

Referring now to Fig. 2, the flyer unit 10 includes two flyer supportingstuds, designated generally by the nu* merals 24 and 25 which arejournalled rotatably in bearing blocks 27 and 28, respectively, mountedfixedly on spaced support columns 31 and 32, respectively. Both of theflyer supporting studs 24 and 25 are driven rotatably from the driveshaft 16 by means of conventional sprocket and chain transmissions,indicated generally at 34 and 35, respectively. The flyer supportingstud 24 is provided with an axially extending bore 37 which communicateswith a radially extending slot 38 formed therein. A pair of freelyrotatable guide pulleys 46)-40 are positioned in the slot 38 on oppositesides of the longitudinal axis of the bore 37. The flyer .supportingstud 24 has projecting, opposed, spaced flyer arms 42-42, and groovedguide sheaves 45 and 46 are journalled rotatably between fthe adjacentends of the flyer arms.

The flyer supporting stud 25 is similar in construction to the flyersupporting stud 24 and is provided with a radially extending slot 48, inwhich is positioned a pair of freely rotatable guide pulleys 5tl*5tl.The guide pulleys 50-5ll are positioned on opposite sides of thelongitudinal axis of an axially extending bore 5f formed in the flyersupporting stud 25 in communication with the slot 48. The flyersupporting stud 25 is provided with projecting, opposed flyer arms 52-52substantially identical in construction to the flyer arms 42-42 of theflyer supporting stud 24. Grooved guide sheaves 55 and 56 are journalledrotatably between the adjacent ends of the flyer arms 52-52.

The end `of the flyer supporting stud 24, which extends toward the otherflyer supporting stud 25 is provided with a projection 59 of a reduceddiameter, through which the bore 37 extends completely. The projection59 cooperates with a similarly conflgurated projection 60 provided onthe flyer supporting stud 25 to constitute trunnions for supporting acradle, designated generally by the numeral 65, in position between theflyer arms 42-42 and 52-52 where the cradle remains substantiallystationary during rotation of the yer arms with their respective yersupporting studs 24 and 25 about the cradle.

The cradle 65 includes a rectangular framework made up of twolongitudinally extending side members 69--69 which are secured to andspaced apart at their opposite ends by two crossmembers 70 and 71. Thecrossmem* bers 70 and 71 are provided with aligned apertures 74 and 75,respectively, which the trunnion projections 59 and @h the flyersupporting studs 24 and 25, respectively, are designed to enter tosupport the cradle. The apertures 74 and 75 are positioned so that thecenter of gravity of the cradle lies in a plane below the rotationalaxis of the yer supporting studs.

ln the cradle 65 there are positioned two strand supply reels 81 and 82which are mounted rotatably on reel supporting centers 84-84 between theside members 69-69- Suitable braking devices (not shown) are provided-for controlling the tension on strands 87 and 88 as they are withdrawnfrom the supply reels 81 and 82, respectively, during the operation ofthe strand twisting apparatus. The strand 88, which is withdrawn fromthe Supply reel 82, passes between guide pulleys 89 and 90 mounted onthe cradle 65, which guide the strand to a stranding die 92 positionedin the entrance end of the bore 37 formed in the projection 59. Thestrand 87, which is withdrawn from the supply reel 81, passes directlythrough the stranding die 92 wherein it is twisted with the strand 88 toform a cable, designated generally by the numeral 93.

The cable 93 is advanced through the bore 37 and into the slot 38wherein it passes in a clockwise direction, as viewed in Fig. 2, partlyabout the guide pulley dll, which directs the cable to the guide sheave45 on the flyer arms 4.2*42 The cable 93 is advanced from the guidesheave 45 in a direction opposite to the direction in which it advancedthrough the bore 37 and is directed to the guide sheave 55 on the flyerarms 52-52 from whence it advances partly around the guide pulley 50 andemerges from the flyer unit 10 through the bore 51 in the flyersupporting studV 25. After leaving the flyer unit 10, the cable 93passes completely around the takeup capstan 20 and is linally wound upon the takeup reel 21.

Encircling the cradle 65 between the flyer arms 42-42 and 52-52 arethree equally spaced hoops 95-95 formed from tubular metal stock, suchas aluminum tubing or the like. Each of the hoops 95-95 is supported forrotation concentrically with respect to the rotational axis of the flyersupporting studs 24 'and 25 by an associated equilaterally spacedarrangement of three grooved rollers 96, 97 and 98 (Fig. 3) which arepositioned 120 apart in a common plane perpendicular to the rotationalaxis. The rollers 96-96, 9797 and 98-98 are keyed upon horizontallyextending shafts 101, 102 and 103, respec-V tively, which are spacedequidistantly around the ilyer unit 10.

The shaft 101 is supported freely rotatably at opposite ends thereof bya pair of spaced, projecting bracket arms 1tl7-107- The bracket arms107-107 are connected pivotally to spaced, vertical columns 108-108,respectively, on stub shafts 109-109 Each of the bracket arms 107-107 isprovided with a suitable countenweight 110, which is designed tomaintain the bracket arms in a raised position, as indicated by phantomlines in Fig. 3, whenever the center of gravity of the counterweights ispositioned to the left of the stub shafts 109-109. Normally, the bracketarms 107-107 are in' an operative position, as indicated in Fig. 3 bysolid lines, in which position the rollers 96-96 on the shaft 101 engagethe hoops 95-95.

The shafts 102 and 103 are journalled rotatably on spaced verticalsupport columns i12-112. The shaft Y 4 102 is freely rotatable, whereasthe shaft 103 is driven positively by means of a sprocket and chaintransmission, designated generally by the numeral 114 from a shaft 115.The shaft 115 is driven, in turn, from the drive shaft 16 by means ofintermeshing gears 116 and 117. Each of the hoops 95-95 is drivenrotatably by virtue of the frictional engagement with its corresponding,positively driven roller 98.

As shown in Fig. 2, the inner diameter of each of the hoops 95-95 issubstantially equal to the diameters of the circular paths of travel ofthe support points at which the cable 93 leaves and enters the guidesheaves and 55, respectively. Thus the hoops 95-95 function to restrainthe ballooning of the otherwise unsupported length of cable 93 betweenthe guide sheaves 45 and 55. By virtue of the intermeshing gears 116 and117 the shaft 103'is driven in a direction and at a speed such that thehoops 95-95 rotate in the same direction as the rotating llyer arms42-42 and 52-52 and the peripheral speeds of the hoops and the cable 93at the points of contact therebetween .are substantially equal.

Operation It will be assumed, for the purpose of the followingdescription, thatthe motor 14 has been energized to drive the flyer unit10, and the takeup unit 12. Throughout the operation the takeup capstan20 advances the cable 93, which is formed in the flyer unit 10,continuously to the takeup reel 21 upon which the finished cable iswound for storage. As the takeup capstan 20 advances the cable 93longitudinally, the strands 87 and 88 are Withdrawn from theirrespective strand supply reels 81 and 82 and enter the stranding die 92wherein they are twisted together to form the cable.

Uponemerging from the stranding die 92, the cable 93 advances partlyaround the guide pulley 40 and is directed to the guide sheave 45 on theouter end of the ilyer arms 42-42. From the guide sheave 45 the cable 93advances to the guide sheave 55 on the outer end of the flyer arms 52-52and thence to the guide sheave 50 which directs it through the bore 51toward the takeup capstan 20. For each revolution of the flyer arms42-42 and 52-52 two twists are imparted to the strands 87 and 88.Assuming a given rotational speed of the takeup capstan 20, the speed ofrotation of the flyer arms 42-42 and 52-52 determines the number oftwists of the strands 87 and 88 per unit length of the cable 93, thatis, the greater the speed of rotation of the yer arms the greater thenumber of twists per unit length of the cable.

As the yer arms 42-42 and 52-52 are rotated, the length of cableadvancing continuously between the guide 1 sheaves 45 and 55 tends toballoon and, if it were not for and enters the gunde sheaves 45 and 55,respectively, the

ballooning of the length of cable 93 crossing the span between theseguide sheaves is restrained and the hoops serve to support the cable atthree equally spaced points therebetween. The effect is to break theusual single catenary into four smaller catenaries, whereby tensionalstresses in the cable 93 along the length thereof between the guidesheaves 45 and 55 are greatly reduced. This permits the flyer unit 10 tobe operated at relatively higher operating speeds without danger ofbreakage in the cable 93. It may be seen that any desired number ofhoops -95 may be employed to break the usual masas single catenary intosmaller catenaries, and the tensional stresses in the cable 93 will bereduced accordingly.

` An important feature of this invention is that the loading andunloading of strand supply reels 81 and 82 is made possible by makingthe rollers 96-96 movable manually out of engagement with the hoops95-95, as shown in phantom lines in Fig. 3. The hoops 95--95 may then belifted from the rollers 9797` and 98--98 and shifted longitudinally topermit the strand supply reels 81 and 82 to pass therebetween. Thus thespacing between the hoops 95-95 is not dictated by the size of thestrand supply reels employed.

Moded embodiment Referring now to Fig. 4, there is shown a hoop 295forming a part of a modiied embodiment of the invention. The hoop 295differs in construction from the hoops 95-95 primarily in that the hoop295 has been provided with an antifriction sheave 298. The sheave 298(Figs. 4 and 5) is rotatable freely about a pin 299 supported iatopposite ends thereof between the sides of a U-shaped, combinationsupport and guard, designated generally by the numeral 300, which isattached iixedly to the hoop 295. The sheave 298 is designed so that itsweight is a minimum and the weight distribution of the hoop 295 isbalanced preferably by internally disposed weights (not shown)positioned suitably therewithin.

Operation of the modified embodiment In strand twisting operationsinvolving strands having outer surfaces which possess relatively highcoeiiicients pf friction, it is desirable to utilize a hoop like thehoop 295 in place of each of the hoops 95-95. Assuming that three hoopslike the hoop 295 have been substituted for the three hoops 95--95 ofthe apparatus described in the first embodiment ofthe invention, thecable 93 will advance longitudinally on the sheave 298 secured to eachhoop during the twisting operation, whereby the friction issubstantially reduced at the points at which the hoops support thecable. Since the sheave 298 on each hoop 295 must be aligned preciselyat all times during the operation with the sheave on every other hoop,it is important that the hoops be rotated in synchronism by suitablemeans.

Manifestly, the embodiments of the invention hereinabove described areillustrative only and may be moditied and departed from in various wayswithout departing from the spirit and scope of the invention.

It will be understood that although the above-described embodiments ofthe invention include three hoops, the

invention is not limited to any specific number of hoops.

For example, in some applications it may be expedient to use only one ortwo hoops, whereas in other applications it may be expedient to use fouror more hoops.

In the above-described embodiments, the hoops have been described ashaving been constructed from tubular stock to reduce the weight thereofso that they may be supported and handled more readily. However, it willbe understood that the hoops may be constructed from solid or tubularstock, as desired.

The term twisting as employed in the specification and claims is meantto include twisting, stranding and similar types of operations.

What is claimed is:

l. Strand twisting apparatus, which comprises a strand supply, means forwithdrawing a strand from the strand supply, rotatable flyer means forcarrying a loop of the strand rotatably about the strand supply as thestrand is withdrawn therefrom, a hoop mounted concentrically withrespect to the rotational axis of the flyer means, means for rotatingthe hoop in synchronism with the rotational flyer means, andantifriction means mounted on the hoop engaging the strand loop andrestraining l the ballooning thereof.

2. Strand twisting apparatus, which comprises a pair of spaced flyermembers rotatable about a common rotational axis, means for advancing agroup of strands from the periphery of one iiyer member to the peripheryof the other, means for rotating the iiyer members in synchronism, ahoop positioned intermediate of the iiyer members and encircling thespan of grouped strands advancing between the iiyer members so as torestrain the ballooning of the strands as the iiyer members are rotated,and means for detachably supporting the hoop for rotation concentricallyabout the rotational axis of the flyer members.

3. Strand twisting apparatus, which comprises a pair of spaced flyermembers rotatable about a common rotational axis, means for advancing agroup of strands from the periphery of one flyer member to the peripheryof the other, means for rotating the flyer members in synchronism, ahoop positioned detachably intermediate of the iiyer members andencircling the span of grouped strands advancing between the yer membersfor restraining the ballooning of the strands as therflyer members arerotated, and means for rotating the hoop concentrically about therotational `axis of the flyer members at a rotational speedsubstantially equal to and in the same direction as the iiyer members.

4. Strand twisting apparatus, which comprises a pair of spaced flyermembers rotatable about a common rotational axis, means for advancing agroup of strands from the periphery of one iiyer member to the peripheryof the other, means for rotating the flyer members in synchronism, aplurality of spaced rotatable hoops positioned intermediate of the.flyer members and encircling the span of grouped strands advancingbetween the iiyer members for restraining the ballooning of the strandsas the flyer members are rotated, and means for supporting the hoops forrotation concentrically about the rotational axis of the iiyer members.

V5. Strand twisting apparatus, which comprises a pair of spaced flyermembers rotatable about a Vcommon rotational axis, means for advancing agroup of strands from the periphery of one iiyer member to the peripheryof the other, means for rotating the flyer members in synchronism, aplurality of spaced rotatable hoops positioned detachably intermediateof the iiyer members and encircling the span of grouped strandsadvancing between the iiyer members for restraining the ballooning ofthe strands as the iiyer members are rotated, and means for supportingthe hoops for rotation concentrically about the rotational axis of theiiyer members.

6,. Strand twisting apparatus, which comprises a pair of spaced iiyermembers rotatable about a common rotational axis, means for advancing agroup of strands from the periphery of one iiyer member to the peripheryof the other, means for rotating the iiyer members in synchronism, aplurality of spaced hoops positioned intermediate of the iiyer membersand encircling the span of grouped strands advancing between the flyermembers for restraining the ballooning of the strands as the liyermembers are rotated, and means for rotating the hoops concentricallyabout the rotational axis of the iiyer members at rotational speedssubstantially equal to and in the same direction as the flyer members.

7. Strand twisting apparatus, which comprises a pair of spaced flyermembers rotatable about a common rotational axis, means for advancing agroup of strands from the periphery of one iiyer member to the periph-.ery of the other, means for rotating the iiyer members 1n synchronism,a plurality of spaced hoops positioned detachably intermediate of theflyer members and encircling the span of Urouped strands advancingbetween the iiyer members for restraining the ballooning of the strandsas the iiyer members are rotated, and means for rotating the hoopsconcentrically about the rotational axis of the yer members atrotational speeds substant1ally equal to and in the same direction asthe iiyer members.

8. Strand twisting apparatus, which comprises a pair of spaced llyermembers rotatable about a common rotational axis, means for advancing agroup of strands from the periphery of one iiyer member to the peripheryof the other, means for rotating the flyer members in synchronism, aplurality of hoops positioned intermediate of the flyer members andencircling the length of grouped strands passing between the yer membersso as to restrain the ballooning of said strands when the yer membersare rotating, a plurality of rollers spacedA around the hoops inperipheral rolling engagement therewith and designed to rotatablysupport the hoops concentrically with respect to the rotational axis ofthe flyer members and in spaced relation to one another, and means forrotatably driving at least one roller in contact with each of the hoopsto rotate the hoops simultaneously at rotational speeds substantiallyequal to and in the same direction as the flyer members.

9. Stnand twisting apparatus, which comprises a pair lof spaced i'lyermembers rotatable about a common rotational axis, a cradle positionedlloatingly between the flyer members, a plurality of strand supply reelsmounted on the cradle, means for withdrawing the strands simultaneouslyas ya group from their supply reels, guide means for directing thegrouped strands from the periphery of one ilyer member to the peripheryof the other, means for rotating the iyer members in synchronism wherebythe grouped strands are twisted together by being carried bodily aroundthe cradle, a plurality of hoops positioned intermediate of the llyermembers and encircling the length of grouped strands passing between theyer members for restraining the ballooning of said strands when theflyer members are rotating, aplurality of rollers spaced around thehoops in peripheral rolling engagement therewith and designed torotatably support the hoops concentrically with respect to therotational axis of the llyer members and in spaced relation to oneanother, means for rotatably driving at least one roller in contact witheach of the hoops to rotate the hoops simultaneously at rotationalspeeds substantially equal to and in the same direction as the llyermembers, and means for disengaging the hoops from their respectivesupporting on the cradle.

10. Strand twisting apparatus, which comprises a pair` of spaced yermembers rotatable about a common rotational axis, a cradle positionedfloatingly between the flyer members, a plurality of strand supply reelsmounted on the cradle, means for withdrawing the strands simultaneouslyas a group from their supply reels, guide means for directing the groupstrands from the periphery of one ilyer member to the periphery of theother, means for rotating the flyer members in synchronism wherebyl thegrouped strands are twisted together by being carried bodily around thecradle, a plurality of tubular hoops positioned intermediate of thellyer members and encircling the length of grouped strands passingbetween the flyer members, antifriction sheaves mounted on the hoops forrotation therewith and designed to rollingly engage the strands andrestrain the ballooning of staid strands when the iiyer members arerotating, a plurality of rollers spaced around the hoops in peripheralrolling engagement therewith and designed to rotatably support the hoopsconcentrically with respect to the rotational axis of the yer membersand in spaced relation to one another, means lor rotatably driving atleast one roller in contact with each of the hoops to rotate the hoopsin synchronism at rotational speeds equal to and in the same directionas the llyer members, and means for disengaging the hoops from theirrespective supporting rollers so that the individual hoops may beshifted axially to allow strand supply reels to be loaded and unloadedon the cradle.

References Cited in the le of this patent UNITED STATES PATENTS 843,448Fahr Feb. 5, 1907 2,477,690 French Aug. 2, 1949 2,796,726 Klein lune 25,1957 FOREIGN PATENTS 68,534 Netherlands Aug. 15, 1951 745,096 FranceFeb. 7, 1933 ...man

